The invention relates to speech recognition.
Speech recognition systems analyze a person's speech to determine what the person said. In a typical frame-based speech recognition system, a processor divides a signal derived from the speech into a series of digital frames, each of which corresponds to a small time increment of the speech. The processor then compares the digital frames to a set of speech models. Each speech model may represent how a word is spoken by a variety of speakers. Speech models also may represent phonemes that correspond to portions of words. Phonemes may be subdivided further within the speech model into phoneme elements (PELs), also known as phoneme nodes. Collectively, the constituent phonemes for a word represent the phonetic spelling of the word.
The processor determines what the speaker said by finding the speech models that best match the digital frames that represent the person's speech. Speech recognition is discussed in U.S. Pat. No. 4,805,218, entitled "METHOD FOR SPEECH ANALYSIS AND SPEECH RECOGNITION," which is incorporated by reference.